As a tank (a pressure container) which is used for the storage of hydrogen or the like, there has been utilized a tank including an FRP layer in which hoop layers and helical layers are alternately laminated on the outer periphery of a liner. Each of the hoop layers is a layer formed by hoop-winding fiber bundles (e.g. bundles of carbon fibers) (a winding way of winding the fiber bundles around a tank trunk part substantially vertically to a tank axis), and each of the helical layers is a layer formed by helically winding the fiber bundles (a winding way of winding the fiber bundles up to a tank dome part substantially in parallel with the tank axis) (see FIG. 2, etc.).
When the fiber bundles are wound around the surface of the liner by a filament winding method, it is required to simultaneously wind the plurality of fiber bundles and as uniformly as possible, and hence there has been utilized a multiple-filaments feeding type filament winding device which can simultaneously feed the plurality of fiber bundles. In the multiple-filaments feeding type filament winding device, a plurality of fiber feeding ports called eye ports which perform a forward-backward movement, a right-left movement and rotation are arranged at equal intervals in the form of a ring around a mandrel. When the mandrel is rotated around the center of these eye ports, the plurality of fiber bundles can simultaneously be wound around the mandrel and as uniformly as possible. When the multiple-filaments feeding type filament winding device is utilized, time required for the filament winding can noticeably be shortened, as compared with a usual one-eye port (monofilament feeding) equipment.
Heretofore, as the multiple-filaments feeding type filament winding device, there has been suggested a device including a helical winding head to helically wind the plurality of fiber bundles around the mandrel, and this helical winding head includes at least two guide lines constituted of a plurality of guide portions arranged along a peripheral direction of a mandrel, and a position change mechanism which relatively rotates the respective guide lines to make positions of the respective guide portions changeable (see e.g. Patent Document 1)